Habitat degradation and loss have affected many species across all major groups in India and elsewhere. However, the water birds are among the most impacted in terms of habitat loss and drastic decline in populations. The White-bellied heron (A. insignis) (WBH), a Critically Endangered and top conservation priority species, has lost much of its habitat throughout its range and restricted to small and isolated forests habitats. Hence, we attempted to evaluate the changes in habitat and area of occupancy in its entire distribution range using a binary ensemble of both past and present models. We observed a drastic loss in the habitat of WBH by 59.18% in the last century, out of which the novel niche occupied, was around 12,139 km² in the northern undisturbed areas. The Centroid shift in its range reveals a notable shift in the north and north-eastern areas current in relation to its past distribution. The loss of suitable areas was highest in its range in India, followed by Myanmar and Bangladesh. Whereas in the present scenario, northern areas of Bhutan tend to become more suitable for the species (60% gain), and species may occupy novel niches in the northern region of Bhutan. The Precipitation of Warmest Quarter (bio_18), water runoff in the river and human footprint in its habitat were the significant predictors of the species habitat in the past and present scenario. We speculate that the species might lose some of the evolutionary traits meant for group foraging fish-eating birds because of this shift in range. The species largely occupy forested areas along the fast-flowing rivers such as Namdapha and Lohit in Arunachal Pradesh. We hypothesize that prolonged isolation by sticking to fast-flowing rivers only inside remote areas without much interaction from other group foragers driving WBH to extinction in India and possibly across its range.

栖息地退化和丧失影响了印度和其他地方所有主要群体的许多物种。然而，水鸟在栖息地丧失和种群数量急剧下降方面受到的影响最大。白腹鹭 ( A. insignis ) (WBH) 是一种极度濒危和优先保护的物种，在其整个活动范围内失去了大部分栖息地，并仅限于小而孤立的森林栖息地。因此，我们尝试使用过去和现在模型的二元集合来评估栖息地和占用面积在其整个分布范围内的变化。我们观察到 WBH 的栖息地在上个世纪急剧减少了 59.18%，其中新的生态位占据了大约 12,139 km ²在北部未受干扰的地区。其范围内的质心偏移揭示了北部和东北部地区当前与其过去分布相关的显着变化。其范围内适宜地区损失最多的是印度，其次是缅甸和孟加拉国。而在目前的情况下，不丹北部地区往往更适合该物种（增加 60%），物种可能会在不丹北部地区占据新的生态位。最暖季降水量 (bio_18)、河流径流及其栖息地中的人类足迹是过去和现在情景中物种栖息地的重要预测因子。我们推测，由于这种范围的变化，该物种可能会失去一些用于群体觅食食鱼鸟类的进化特征。该物种主要占据阿鲁纳恰尔邦的 Namdapha 和 Lohit 等水流湍急的河流沿岸的森林地区。我们假设仅在偏远地区坚持快速流动的河流而没有与其他群体觅食者进行太多互动，从而导致 WBH 在印度及其范围内灭绝，从而延长了隔离时间。